The present invention relates to a tool shank mounting assembly for the mounting of shanks of earth working tools.
It is a common procedure to mount shanks of earth working tools to tool bars of agricultural equipment. It is desirable that the vertical height of the shank and thus the tool carried by the shank be conveniently adjustable. It is also desirable that the mounting arrangement for the shank firmly holds the shank in place when operating the shank and coupled tool in the ground. Tools which are attached to shanks in many cases can have considerable span to either side of the shank. Tools of this type, tend to apply twisting loads to shank and thus the shank mounting arrangement.
A common system for mounting shanks is to provide a series of holes in the shank, with cheek plates provided on opposite sides of the shank and mounted to the tool bar and bolts which are passed through the cheek plates and a selected hole or holes in the shank to set the height of the shank and clamp the shank in position. Vertical adjustment of the shank in such an arrangement is time consuming as the bolts have to be removed to allow the shank to be adjusted in height and then reinserted in a further hole or holes and through the shank. Further, the formation of such holes generally reduces the strength of the shank. In another system, serrated tracks are provided in the rear of the shank which is again clamped between two cheek plates. Bolts which clamp the plates together also cooperate with the track for positive height location of the shank. This arrangement is also time consuming to adjust and height of the shank in this system is limited by the spacing of the serrations. In yet a further arrangement, the tool shank is frictionally gripped between a pair of cheek plates which are clamped by bolts onto opposite sides of the shank. Cheek plates where used are difficult to keep tight when subject to inevitable asymmetric side loads.
The present invention aims to overcome or alleviate one or more of the above described disadvantages or at least provide an alternative to the current shank mounting systems. It is a preferred object of the present invention to provide a mounting assembly which will allow for the quick and easy adjustment of the height of shanks and tools carried thereby. It is another preferred object of the present invention to provide an assembly which will provide a secure mounting for the shank and which will withstand large side loads which are incurred by the shank. Other objects, aspects, and advantages of the present invention will be apparent from the following description.
The present invention thus provides in one aspect, a mounting assembly for mounting the shank of an earth working tool, said assembly comprising:
a shank holder having a passage therethrough adapted to receive said shank, said passage having at least one side wall,
a wedge member adapted for wedging between said shank and a said side wall of said passage to secure said holder to said shank at a selected position along said shank, and
means for selectively urging said wedge member longitudinally of said passage.
Preferably, the passage tapers in cross section inwardly from at least one end. Suitably the wedge member is adapted to cooperate with the tapered passage such that when urged longitudinally of the passage, the wedge member moves in parallelism inwardly towards the adjacent edge portion of the shank to wedge the shank in position. The urging means may include a bolt between the wedge member and holder.
The present invention in a further aspect provides a mounting assembly for mounting the shank of an earth working tool, said assembly comprising:
a shank holder having a passage therethrough adapted to receive said shank, said passage having at least one side wall,
a pair of wedge member adapted to be located at opposite ends of said passage for wedging between said shank and a said wall of said passage to secure said holder to said shank at a selected position along said shank, and
means for selectively urging said wedge members longitudinally of said passage and towards each other.
Preferably in this aspect, the passage tapers in cross section inwardly from one end of the passage towards a point substantially halfway along the passage and then tapers outwardly to the other end of the passage. The tapers in the passage are suitably defined by an end wall of the passage which is inclined or angled inwardly relative to the longitudinal axis of the passage from one end towards the point substantially halfway along the passage and then is inclined or angled outwardly to the opposite end of the passage.
The pair of wedging members are adapted to be received between the leading edge portion of the shank and the tapering walls of the passage which define therebetween tapering spaces so that the shank is wedgingly held at spaced positions. Separate means may be provided to urge the wedging members in opposite directions relative to the longitudinal axis of the passage. The separate urging means may comprise bolts between the wedging members and holder. For this purpose, the wedging members may include apertured end plates and the holder is provided with aligned apertures, preferably provided in flanges, to receive the bolts.
Alternatively, single urging means such as a bolt may be provided between the wedging members to urge the wedging members longitudinally and relatively towards each other. The single urging means may comprise a bolt which passes through the apertured end plates of the wedge members and the apertures in the holder. Tightening the bolt will thus urge the wedge members towards each other to firmly wedge the shank in position.
Preferably, the passage in cross section is generally complementary to the cross sectional form of the shank and suitably includes opposite side walls which are spaced apart a distance slightly greater than the spacing between the front and rear, or leading and trailing edges of the shank.
Suitably the opposite ends of the passage are of V-shaped cross section and the leading edge portion of the shank is also of V-shaped cross section. Preferably, the V-shaped ends and edge portion have an included angle of approximately 90 degrees. Each wedging member preferably includes a leg which is of V-shaped cross section and complementary to the V-shaped cross section of the passage and shank leading edge portion. The leg of the wedging member is preferably of tapering form in cross section to match the inclination of the inclined surfaces of the passage such that when the wedging member is moved slidably into the passage in contact with the inclined end of the passage, the leg of the wedging member moves inwardly in parallelism. This is achieved by having the operative forward V-sectioned surface of the wedge member at an inclination matching the inclination of the complementary inclined surface of the passage. The rear V-shaped surface of the wedging member preferably extends substantially parallel to the longitudinal axis of the passage and thus to the longitudinal axis of the shank so that the leg of the wedging member engages the leading edge of the shank along its full length. Where two wedging members are employed, this is achieved at spaced apart positions in the passage.
The opposite end wall of the passage may also be of V-shaped cross section for cooperation with a similarly shaped V-shaped trailing edge of the shank. Again the V-shaped cross sections have an included angle of approximately ninety degrees.
The V-shaped cross section of the leading edge of the passage and complementary form of the wedge and shank provides a substantial surface (defined by the faces of the V""s) to resist twisting loads applied to the shanks. A similar effect can be achieved by substituting for the V-shaped cross sections of the shank, holder passage and wedge members, a part-circular cross section or a multi-surface cross section or any other sectional form which will resist twisting loads on the shank.
The present invention in yet a further aspect provides in combination a tool shank and tool holder, said tool shank having a leading end of substantially V-shape in cross section, and said tool holder having a passage therethrough receiving said tool shank, the leading end of said passage being of V-shape in cross section, and a pair of pair of wedge members at opposite end of said passage, each said wedge having a leg portion of V-shaped cross section extending between said leading end of said passage said tool shank, and means for selectively urging said wedge members into said passage.
Preferably the leading end of the passage is inclined inwardly towards the leading end of the shank from the opposite end of the passage to define openings of tapering cross section for receipt of the leg portions of the wedge members. Preferably, the leg portions of the wedge members have a corresponding taper in cross section.